At present, it is known to prepare a copolymer consisting of the reaction product of bis(3,5-dimethyl-4-hydroxyphenyl)sulfone; 2,2-bis(4-hydroxyphenyl)propane and a carbonate precursor. U.S. Pat. No. 3,737,409 describes a process for making such a copolymer, which is disclosed to lend itself to the preparation of textile fibers.
U.S. Pat. No. 4,286,075 describes a molding composition comprising blends of polyarylates derived from a dihydric phenol and mixtures of terephthalic acid and isophthalic acid, and at least one thermoplastic polymer compatible therewith. A blend of the polyarylates and an aromatic polycarbonate, where a thermoplastic compatible polymer is optionally added is also mentioned.
Polymer mixtures such as polycarbonates based on 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane and ABS type addition polymers were disclosed to have better molding properties than mixtures where the polycarbonate was based upon 2,2-bis(4-hydroxyphenyl)propane, in U.S. Pat. No. 4,172,103. Such blends however showed a decrease in the elastic modulus.
Broadly disclosed, but not claimed, also are mixtures comprising mixed polycarbonates and thermoplastic resins. However, no data on the physical properties of these such mixtures can be found in said patent.
When compositions suggested by the disclosure in U.S. Pat. No. 4,172,103 were proposed, as will be shown hereinafter, they were inferior in certain important physical properties. e.g., resistance to distortion by heat and mechanical properties such as stiffness and strength.
In applicant's concurrently filed copending application, Ser. No. 451,180 filed Dec. 20, 1982, now U.S. Pat. No. 4,510,289, there are disclosed and claimed novel compositions comprising mixed polycarbonates and thermoplastic condensation polymers, alone or in further combination with addition polymer containing hetero groups which are admixed to provide compatible compositions.